Drive circuit for liquid crystal display device

Abstract

A liquid crystal display device includes a liquid crystal display, which has a plurality of liquid crystal elements arranged in a matrix and has signal electrodes and scanning electrodes provided with respect to the liquid crystal elements. A signal electrode driver, for driving the signal electrodes of the liquid crystal display, has a driver and a switch circuit. This switch circuit comprises groups of switches connected in multi-stages in the column direction. Each switching stage includes a plurality of switches, the number of which increases from one stage to another toward the final stage. The switches of the first switching stage have their input terminals supplied with video signals, respectively. The output terminal of each switch of one switching stage is branched and coupled to the input terminals of associated switches of the succeeding stage. The output terminals of the switches of the last switching stage are respectively coupled to the signal electrodes. The actuation of the switches of each switching stage is controlled by a driver such that they are sequentially activated one at a time.

What is claimed is: 
     
       1. A drive circuit for a liquid crystal display device, comprising: input means for receiving a signal to be displayed;   liquid crystal display means having a plurality of liquid crystal elements arranged in a matrix and having scanning electrodes and signal electrodes provided with respect to said liquid crystal elements;   scanning electrode driving means, coupled to said scanning electrodes, for sequentially driving said scanning electrodes;   a plurality of switching stages, coupled in columns, each of which includes a plurality of switch means, each of said switch means of the first switching stage having an input terminal coupled to said input means and having an output terminal branched so that said output terminal is coupled to input terminals of associated switch means located in a succeeding switching stage, and output terminals of said switch means of the last switching stage being respectively coupled to said signal electrodes; and   drive control means, coupled to each of said switch means, for sequentially activating said switch means of said each switching stage one at a time in such a manner that said signal electrodes are sequentially driven by said signal to be displayed.   
     
     
       2. The drive circuit according to claim 1, wherein said drive control means controls said switch means such that each of said switch means of one switching stage is kept activated until all of those switch means of the succeeding switching stage which are coupled to said each switch means of said one switching stage, are sequentially activated. 
     
     
       3. The drive circuit according to claim 2, wherein, with the number of said signal electrodes being N (N: a positive integer), the number of said switch means of said first switching stage is close to √N and the number of said switch means of said last switching stage is N. 
     
     
       4. The drive circuit according to claim 3, wherein the number of said switching stages is two. 
     
     
       5. The drive circuit according to claim 4, wherein each of said switch means is a C-MOS analog switch. 
     
     
       6. The drive circuit according to claim 5, wherein said signal to be displayed is a video signal. 
     
     
       7. A liquid crystal television receiver comprising: reception means for receiving a television signal to provide a video signal on a desired channel;   liquid crystal display means having a plurality of liquid crystal elements arranged in a matrix and having scanning electrodes and signal electrodes provided with respect to said liquid crystal elements;   scanning electrode driving means, coupled between said reception means and said scanning electrodes, for sequentially driving said scanning electrodes in synchronization with one horizontal scanning period of said video signal;   a plurality of switching stages, coupled in columns, each of which includes a plurality of switch means, each of said switch means of the first switching stage having an input terminal coupled to said reception means and having an output terminal branched so that said output terminal is coupled to input terminals of associated switch means located in a succeeding switching stage, and output terminals of said switch means of the last switching stage being respectively coupled to said signal electrodes; and   drive control means, coupled to said reception means and each of said switch means, for sequentially activating said switch means of each of said switching stage one at a time, all of said switch means of said last switching stage being sequentially activated during said one horizontal scanning period of said video signal.   
     
     
       8. The liquid crystal television receiver according to claim 7, wherein said drive control means controls said switch means such that each of said switch means of one switching stage is kept activated until all of those switch means of the succeeding switching stage which are coupled to said each switch means of said one switching stage, are sequentially activated. 
     
     
       9. The liquid crystal television receiver according to claim 8, wherein, with the number of said signal electrodes being N (N: a positive integer), the number of said switch means of said first switching stage is close to N and the number of said switch means of said last switching stage is N. 
     
     
       10. The liquid crystal television receiver according to claim 9, wherein the number of said switching stages is two. 
     
     
       11. The liquid crystal television receiver according to claim 10, wherein each of said switch means is a C-MOS analog switch.